[16.0][REF][l10n_br_base][l10n_br_fiscal][l10n_br_account] tests don't depend on demo

[rvalyi]

both Odoo SA and the OCA recommend that tests don't depend on demo data. Here I'm starting this cleanup on the most central modules. Benefits include:

• the test context is simpler and easier to figure out
• this avoids the demo data incompatibility hell where arbitrary modules alter demo data and depending on what modules are installed exactly your tests may fail with no clear explanation
• this allows to run fiscal tests on copy of production databases

We have long wished to achieve that in the project. However, in l10n-brazil we need to maintain both complex fiscal demo data and fiscal test fixtures. That is why until now the test fiscal transactions where based on demo data.

In this PR, I created a simple framework (with l10n_br_base/tests/tools.py and l10n_br_fiscal/tests/tools.py) where we can load the SAME fiscal demo data both for the demo mode and for the tests even on databases created without demo data (like with the --without-demo=all param). I had to clean up a bit useless relations to demo data in the fiscal demo data and work around the demo data of the product module.

As we tend to reload the same fiscal demo fixtures in several tests, tests are a bit slower. But:

• in the future they could actually be faster if we create test database with --without-demo=all
• it's v16 which is 3x faster than v14, so not such a big deal (only a few dozens of extra seconds)
• even if tests do a bit more queries, they are much easier and faster to debug this way...

[OCA-git-bot]

Hi @renatonlima,
some modules you are maintaining are being modified, check this out!